Phase formation, thermal stability and mechanical properties of Nb-B-C thin films prepared by magnetron sputtering using a combinatorial approach
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| Year of publication | 2021 |
| Type | Conference abstract |
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| Description | The performance and lifetime of a tool can be significantly improved by the use of an appropriate protective coating. The most commonly used materials for these applications are ceramic-based coatings, favoured due to their high hardness. However, these coatings are inherently brittle which enables the spreading of cracks and coating failure. Therefore, new materials are being explored, which would combine the hardness of ceramics with a degree of ductility. Ab-initio calculations have predicted that such a combination of properties could be present in a crystalline X2BC material where X is a transition metal such as Mo, Ti, V, Zr, Nb, Hf, Ta or W [1]. Out of this group, only crystalline Mo2BC has been successfully prepared and studied so far. There have been attempts to prepare a W2BC phase but these remain unsuccessful due to the near-zero enthalpy of formation of this material. However, these studies have shown that the X-B-C system exhibits interesting mechanical properties even in an amorphous state [2, 3]. This study focuses on the Nb-B-C system as Nb2BC is predicted to have a lower enthalpy of formation. The coatings have been prepared by magnetron sputtering from 3 targets using a combinatorial approach. A wide range of compositions has been studied and evaluated in regard to their structure and mechanical properties. As thermal and oxidation stability is a vital requirement for protective coatings, the studied coatings have been annealed up to 900°C in argon and up to 1000°C in an Ar/O2 gas mixture. The study examines the effect of annealing on the structure and mechanical properties of the coatings. |
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